Low Intensity Shockwaves (LISW) applied to soft tissue is known to increase blood flow in the tissue. LISW has been used to treat erectile dysfunction (ED), by increasing blood flow to the corpus cavernosum. Normal erectile function requires adequate penile arterial inflow, sufficient corpora cavernosal expansion, and competent venous sinusoidal outflow occlusion. By permitting blood to flow into but not out of the corpus cavernosum, the venous sinusoidal mechanism can transform the corpus cavernosum from an open to a closed chamber capable of trapping blood and thus producing rigid erections.
Prof. Yoram Vardi, head of the neuro-urology unit at Rambam Medical Center in Haifa, Israel, has demonstrated the efficacy of LISW to treat ED (see, for example, “Penile Shockwave Therapy Helps Men With Severe Erectile Dysfunction”, Medscape, Mar. 22, 2011, which may be found at http://www.medscape.com/viewarticle/739414). The patient is in a supine position on a treatment table. The operator manually presses a transducer head laterally against the penile shaft while the shaft is firmly held by the operator's other hand. Shockwaves, geometrically focused to a focal point, are applied at several locations along the shaft and at the lower abdomen for treating the crus penis (the part of the corpus cavernosum inside the body). For example, during each treatment session, low-energy shockwave therapy is applied to the penile shaft and crus for 3 minutes in 5 different penile anatomical sites. The shockwaves are generally one tenth the level of intensity as shockwaves used to pulverize kidney stones.
Shockwave devices typically generate shockwaves that converge on a single focal point. Consequently a focal therapeutic volume in the shape of an ellipsoid is created where the long ellipsoid axis coincides with the beam propagation direction and the width of the therapeutic volume is in the order of few mm. This has been adequate in the treatment of stones or orthopedic conditions. However, for treating ED there are major drawbacks: the target is the two corpora cavernosa—shaped like elongated cylinders, located partially in the penis and continuing inside the body as to form the penis crura. A shockwave transducer incorporating a therapeutic focal point must be moved to multiple positions along the penis. Attaching such a transducer head to the lower abdomen so as to apply shockwaves to the crura is geometrically inefficient since the crura are positioned at the lower part of the pelvis, somewhat parallel to the perineum.
A subsequent development (the RENOVA system, manufactured by Initia Ltd. of Israel) treats the crus by coupling a transducer head to the perineum of a patient in a lithotomy position. To effectively optimize shockwave application to the penis and crura anatomy, RENOVA uses linear shockwave therapy (LSWT) incorporating means to focus shockwaves along a linear segment. LSWT enables generation of a 70 mm long treatment volume along the target organ as opposed to the traditional focal point generated by all other shockwave devices.
In all of the known prior art, the patient is lying on his back, the penis is positioned vertically, the shockwaves propagate horizontally and attachment pressure is applied by pressing the transducer against the patient. The attachment pressure, i.e., the pressure applied by the flexible membrane of the transducer head when pressed against the patient, is an important parameter affecting the efficacy of the shockwaves transmission to the patient. Typically, the higher the attachment pressure—the higher the fraction of the shockwaves propagating into the patient. A thin layer of air or air bubbles between the transducer head and the patient may block the propagation.
Consequently, prior art devices rely on an operator—a physician or a technician—to provide the required attachment pressure.
For the purpose of this invention, low intensity shockwaves are pulsed acoustic waves whose wave front is not necessarily steep as is characteristic of high intensity shockwaves.